Cardiovascular disease (CVD) is the world's leading cause of morbidity and mortality, and evidence is mounting that sleep disturbance-which is chronically experienced by approximately one-third of the adult population-may be a prominent risk factor. The majority of research thus far has focused on the cardiovascular consequences of sleep disordered breathing, though there is compelling epidemiologic evidence that insomnia, particularly insomnia with short sleep duration, may be associated with increased CVD risk. Identification of increased CVD risk for this sleep phenotype would have significant